Induction-motor.



K. A. PAULY.

INDUCTION MOTOR. APPLICATION IILED MAR.8 1,1911.

1,067,270. Patented July 15, 1913.

AW HBET 1.

C a J i Witnsses I Inventor:

K. A. PAULY.

INDUCTION MOTOR.

APPLIOATION FILED MAR.31,1911.

1,067,270, Patented Ju1y15, 1913.

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Witnesses Inventor;

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UNITED s ATEsj SCHENECTADY, QY BK, Assiciio nj COMPANY, A ooprorterwn or new ironic KARL A. PAULY, OF

INDUCTION-Moron.

To all whom it may concern: 1

Be it. known that I, KARL A. PAULY, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Induction-Motors,

of which the following is a specification.

My invention relates tovariable speed induction motors, and its object is to provide a? a in the art, in which the relative direct-ion of current tlow is reversed in half the coils of each phase to vary the number of poles in the ratio of two to one. In such motors it has been customary heretofore either to employa squirrel cage winding, which of course adapts itself to any number of poles, or, it a starting resistance is required for operation on both speeds, to provide a rotor with six collector rings. The reason for employing six collector rings is that with rotor windings as heretofore arranged in such motors, it is necessary to use a six phase rheosta-t, or to vary the connections of the rotor coils when changing from one speed to the other, since, it the rotor coils are properly connected IEOIEOUB number of poles, they will be non-inductive to the stator winding for the othernumber ofpoles.

By my invention I so. arrange circuits that without any change in their connections they are in inductive relation to the stator winding for both sets of poles. I accomplish this by forming each phase of the rotor winding in a plurality of groups of coils connected in a plurality ofclrcuits, each circuit. comprising .a plurality of Y that groups displaced from each other, their voltages are out of fliase, the placement being of such an amount 't-ha the sum ofthe induced voltages of the coil gi tipsis greatenthan Zero tor both'nu1nbers' of;poles.

Specification of Letters Patent,

the rotor I invention will best be unders od-by tAL ELECTRIC reference to the accompanying drawings, in Wlnch- Figure 1 shows diagrammatically an in-.

duction motor arranged in accordance withmy invention; Figs. and 3 are explanatory diagrams; and Fig. 4 shows a development of the windings of a motor like that shown in Fig. 1.

In the drawing, A A, B B and C C represent the three phases of the stator winding of an induction motor, each phase consisting of two groups of coils, as A and A, from which connections are led to the control switch D which is shown diagrammatically with its contacts developed on a plane surface. This switch is arranged to vary the connections of the groups of coils Patented July 15,1913. 1

Application filed March 31, 1911. Serial No. 618,179. J

so as to reverse the relative direction of curv 4 is moved to bring the left handmovabl'e contacts in engagement with the stationary contact fingers, the source of current (indicated by the line wires E) is connected by means of the leads 7, 8 and 9 to the connections between the groups G and B, B and A, and A and G, the leads 10,11'and12being open, the winding being thus"connected' indelta,

so that the current 'passes--t-hrough the two groups of each phase finseries hen the switch D is thrown to bring t'hjej right hand movable contacts into engagement with the stationary contact fingers, the source of current is connected by means of the leads 10,

:11 and 12 to the junction point of the two groups of each phase, the leads 7, 8 and 9 being connectedixrgether to form a neutral point for the winding. fl he-"gcurrent then in each phase flows lphegunoti'ofi point of a it a are' propps the number of velopment of a primary winding for a four pole-eight pole motor having three coils per phase per pole. The rotor winding is also connected three phase, and eachphase consists'of two groups of coils. 1 One phase consists of the coil groups a and a; the second of b and b; and the third of c and They displacement of these three phases is of the usual amount, and if the motor be consideredas operating with the smaller number of poles, the displacement is then 120 elec: trical degrees. When the motor is operating with the larger number of poles, this makes the relative-displacement 2 electrical de grees.

. circuits, each comprising groups'of coils from two different phases. Thus, 'for instance, one circuit comprises the coils a and 0', another 6 and a; and thethirdc and 1;. Furthermore, the'two groups of coilsin' each circuit are reversely connected. The result of this connection oh the voltages of the three circuits is indicated diagrammatically other at an angle of 60, as shown.

in Fig. 2, the coils a and 0 being connected in series and their induced voltages being 120 out of phase their voltages add to eii ih e same is true of each of the othercircuits, so

that the resultant voltages of the rotor cir-.

cuits are nearly as great as though the coils of each phase were connected in series by themselves, in the usual manner.

The 'efiect on the rotor voltages of varying the number of poles may be understood by comparing Fig. 3.with Fig: 2. Since vwith the smaller number of poles the voltages of coils a. and b differ by 120?, they will now difi'er 240 with the largernumber of poles, as is indicated by comparing these two figures. Similarly, if the difference between the coils a and c is 2s0 with the-smaller. number ofpoles, then with the larger number ofpoles they will differ 480,

or,- what is the same thing 120; Thus,

- comparing the lines, a, b, cin Figs. 9. and

3, itwill be seen that the lines representing coils b and c have simply changed. places.

Coils a being still in phase with coils 0 and connected up as before, will have voltages induced in'them in the same direction and will add their voltages to those of coils a at an angle of l20' ,as shown in Fig.

The rotor Winding is 'connected in three relative connections of saidgrou As I have shown the con- Since the voltages in each circuit add to each other effectively for both numbers of poles, the terminals of the circuits may be connected permanently to three collector rings, as indicated at F in Fig. 1,and tothese collector rings,by means of brushes f, a starting resistance G, may be connected, which may, therefore, be used with either number of poles. In the lower part ofFig. 4 is shown the development of a rotor winding hav- ,-1ng four coils per pole per phase, connected up as described above. I

The principle on which my invention is based may be worked out through many differentarrangements, and I do not desire to limit myself to the specific rotor connections which I have shown and described as one suitable embodiment of my invention, but I aim in the appended claims to cover all.

modifications which are within the scope of my invention.

' What I claim as new and desire to secure 7 byLetters Patent of the United States, is

1. In an induction-motor, a stator winding havingits coils connected in groups, connections for said groups forv.rying the to-vary the number of poles in the stator winding,

and a polyphase rotor winding, each phase I 7" ofawhichj comprises a plurality of groups of coils connected in a plurality" of circuits, each of said circuits comprising a plurality of groups of coils in series displaced 'from each other so that their voltages are out of phase. I

2.. In an inductidn motor, a stator winding having the coils connected in groups, connections for said groups for varying the relative connections of said groups to vary. the number of poles inthe stator winding,

and a polyphase rotor winding, each phase OfjVhlCh comprises a plurality of roups of coils connected in a plurality of circuits, each of said circuits comprising a plurality of groups of coils in series displaced-from each other 'so that their voltages are out of phase, collector rings to which the terminals of the rotor circuits are connected, and a starting resistance connected to said col lector rings.

I. 3. In'an induction. motor, a stator winding having its coils connected in groups, connections for said groups for vary ng the relative connections of-said groups to vary the number of poles in the stator winding,

and a polyphase rotor winding, each phase of which comprises a plurality of groups of coils, each group is each phase being connected in a series clrcuit with a group in a ,diflerent phase. I

4. In an induction motor, a stator windmg having its coils connected in groups,

connections for said groups for varying the a resistance connected to said collector rings.

In an 1nduction motor, av stator W111d' 111g having CO1lS connected in groups, connections forsaid groups for varying the two'to one, and a relative connections of said groups'to vary the number of poles, ,in the stator winding, and a polyphase rotor windingv having groups of coils in each phase connected in a plurality of circuits, each of said circuits comprising groups'of coils having different phase relations with different numbers of poles in the stator winding. T v. v

6. In an induction motor, a three phase stator winding, connections for hanging the speed of vary the number of poles in the ratio of three phase'rotor winding the coils of the three phases being displace fromeach other 120 electrical degrees for the srnallernumber of poles, and 240 electrical degrees for I poles, the coils being connected in three cirphases, he coils of one phase being rethe larger number of cuits, each circuit comprising coils of two versely connected relative to the coils of the otherphase in the same circuit.

7. In an induction motor, a three phase stator winding, connections for changing the speed of said motor by reversing the relative direction of current flowing in one half of each phase of the stator winding to vary the number of poles in the ratio of two to one, and a three phase rotor winding,

the coils of the three phases being displaced from each other 120 electrical degrees for the smaller number of poles, and 240 electrical degrees for the larger number of poles, the coils being connected in three circuits, each circuit comprising coils of two phases, the coils ofQone phase being reverselyconnected relative to the coils of the other phase in the same circuit, collector rings to which the terminals of the rotor circuits are connected, and a starting resistance connected connected in a,

to said collector rings;

8. In an induction motor, a stator winding having its coils connected in groups,

connections for said groups for varying the relative connections of said groups to vary the number of poles in the stator winding, and a polyphase rotonwinding, each phase i coils connected mg suchthat the voltages vof the groups-are one connection of the primary wm sald motor by reversing the" relative direction of current fiowingin one. half of each phase of the stator winding to coils of one 1 the same circuit.

of which comprises a plurality of groups of coils connected in a plurality ofcircuits, each of said'circuits comprising a plurality of groups of coils in series; displaced from each other so that their voltages are out of phase}, the amount of such displacement being such that the voltages of the groups are more nearly in series than in opposition for one connection of the primary winding.

9. In aninduction motor, a stator windin havin its coils connected in rou s. D i b I connections for said groups for-varying the ,relativeconnections of said groups to vary the {number of poles in the stator winding,

each phase of pi groups of in a plurality of'circuits, each of said circuits comprising a plurality a polyphase rotor winding, which comprises a plurality -0:? groups of coils in series displaced from each other so-that their .rcltages are out of hase, the amount of such displacement be morenearly in series than in opposition. for

4 ing, collector rings to which'the terminals of the rotor circuits are connected,,and a starting resistance Iconnectedto said collector rings. 10. Inan induction, motor, @a polyphase stator winding, connections for changing the speed of said. motor-by reversing the relative direction of current flowing in one half of each phase of the stator-winding to vary the number of poles in the ratio of two to one, and a; polyphase rotorwinding having its coils connected in a pluralityof cir- Cult-S, each circuit comprising coils of two phases.

' llJIn an induction motor, a polyphase stator winding, connections for changing the speed ofsaid motor by reversing the relative direction of current flowing in one half of each phase of the stator winding to vary the number of poles in the ratio of two toone, a polyphase rotor winding having its Y coils connected in a plurality of circuits, each circuit comprising coils oftwo phases, collector rings'to which the terminals of the rotor circuits are connected, and a starting resistance connected to said collector rings.

'12. In an induction motor, a polyphase stator winding, connections for changing the speed of said, motor by reversing the relativedirection of current flowing in onehalf of each base ofthe statorwinding to vary-the number of poles in the ratioof two to one, and a rotor winding having its coils plurality of circuits, each base bein 1 relative to te coils 0% 13, In an induction. motor, a polyphasa stator winding, connection aider changing a circuit comprising coils of two phases, the

reversely connected the other phase in i 10 circuit, collector rings to w ich the terminals 1 HELEN ORFORD.

the speed of said motoi' by reversing-the of the rotor Ci ICIIitSBIG connected, and a relative direction of current flowing in one starting resistance connected ..tosaid 001- half of each phase of the statonwinding to -lector rings. 1 Y vary-the number of poles in the ratio of two ,In witness whereof, I have. hereunto set 5 to one, arotor windingf" having its cfiils 'con my hand this-30th day of March, 1911.

n'ected in a plurality 0 circuits eac circuit T comprising coils of two phases, the coils of KARL AULY' one phase being revensely connected relative Witnesses: to the coils of the other base in the same BENJAMIN B. HULL,

Copies of this patent nmrbe obteined' for five cents eeeli; by addressing the Commissioner intents;

Washington, D. G. 

